129 lines
4.3 KiB
C
129 lines
4.3 KiB
C
/****************************************************************************
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* examples/random/random_main.c
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*
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* Copyright (C) 2013 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <debug.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Configuration ************************************************************/
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#ifndef CONFIG_EXAMPLES_MAXSAMPLES
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# define CONFIG_EXAMPLES_MAXSAMPLES 64
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#endif
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#ifndef CONFIG_EXAMPLES_NSAMPLES
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# define CONFIG_EXAMPLES_NSAMPLES 8
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#endif
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#if CONFIG_EXAMPLES_NSAMPLES > CONFIG_EXAMPLES_MAXSAMPLES
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# warning CONFIG_EXAMPLES_NSAMPLES > CONFIG_EXAMPLES_MAXSAMPLES
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# undef CONFIG_EXAMPLES_NSAMPLES
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# define CONFIG_EXAMPLES_NSAMPLES CONFIG_EXAMPLES_MAXSAMPLES
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#endif
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* rand_main
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****************************************************************************/
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int rand_main(int argc, char *argv[])
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{
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uint32_t buffer[CONFIG_EXAMPLES_MAXSAMPLES];
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int nsamples = CONFIG_EXAMPLES_NSAMPLES;
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ssize_t nread;
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int fd;
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/* One argument is possible... the number of samples to collect */
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if (argc > 1)
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{
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nsamples = atoi(argv[1]);
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}
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/* Clip the numer of samples to the configured buffer size */
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if (nsamples > CONFIG_EXAMPLES_MAXSAMPLES)
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{
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nsamples = CONFIG_EXAMPLES_MAXSAMPLES;
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}
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/* Open /dev/random */
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fd = open("/dev/random", O_RDONLY);
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if (fd < 0)
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{
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int errcode = errno;
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fprintf(stderr, "ERROR: Failed to open /dev/random: %d\n", errcode);
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exit(EXIT_FAILURE);
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}
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/* Read the requested number of samples */
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printf("Reading %d random numbers\n", nsamples);
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nread = read(fd, buffer, nsamples * sizeof(uint32_t));
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if (nread < 0)
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{
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int errcode = errno;
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fprintf(stderr, "ERROR: Read from /dev/randon failed: %d\n", errcode);
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(void)close(fd);
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exit(EXIT_FAILURE);
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}
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/* Dump the sample buffer */
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lib_dumpbuffer("Random values", (FAR const uint8_t*)buffer, nread);
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(void)close(fd);
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return EXIT_SUCCESS;
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}
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